Drive connection



Sept. I8,r 1953 H. BLYDENBURGH 2,651,530

' DRIVE CONNECTION v Filed Feb 21, 1950 ttorneg s Patented Sept. 8, 1953 UNITED STATES PATENTv OF F ICE f l .Y 2,651,530 Y 'Il' y n fnRIvE CONNECTION` Y Y A HaroldLf-Blydenburgh, Detroit,- Mich., assgnor Y to The Moto-Mower Company,l Detroit, Mich., Y acm-poration of Michigan 'Appncaticii'rtrafry 21, 15359, serial No. 145,463

This invention relates to machine elements and, in particular, to'drive connections interposed between a ro-tary shaft anda-rotary mem'- ber such' as a fan, propeller, pulley, cutter blade or like. 'Y l. I ,Y f:,.,, V` Y( ,l

One object of this invention is Vto vprovide a drive connection and processV` of making the same, for-drivingly Vattaching arotary member to a shaft, such as a motor shaft, whereby expensive machining operations are simplified and replaced by simpler welding operations.

Another object is to provide a drive connec- "tion and process of the foregoing character which maintains a predetermined'clearancebetween the stationary portion ofthe-"'motorand the rotary member, so that all danger Aofbinding or rubbing is eliminated.

Another object is to provide a yieldable drive connection oflthe rforegoing character wherein the hub of the drive connection carries friction members which frictionally engage the rotary driven member and transmit power thereto so long as the rotary member does Ynot encounter resistance or load greater than a predetermined amount which will cause the connection to slip.

In the drawings: l 'r n Figure 1 is `a side Yelevation of a, driveconnection for a rotary member, according to one form of the invention, shown as 'applied to apower lawnmower indicated in dotted lines;

Figure 2 is an enlarged central vertical section through the drive Yconnection 'shown in Figure 1, taken along the line 2-2 therein;

Figure 3 is a bottom plan view of the drive -connection and rotary member portion shown in Figure 2;

Figure 4 is a central vertical section through one part of the hub unit of the drive connection shown in Figures 1 to 3 inclusive;

Figure 5 is a bottom plan view of the hub part shown in Figure 4;

Figure 6 is a central vertical section through an annular plug element adapted to be welded or otherwise secured in the collar element shown in Figure 4; and

Figure 7 is a bottom plan view of the annular plug shown in Figure 6.

Referring to the drawings in detail, Figure 1 shows a slipping drive connection, generally designated I0, according to the invention as applied to the drive of a rotary member II, such as the rotary cutter of `a power lawnmower, generally designated I2. The power lawnmower I2 itself is conventional and its details are beyond the scope of the present invention. For the purpose f1 Claim. (Cl. 287-53)V l l v2 of illustrating the presentY invention,'the` power lawnmower I2 may be said to consist of a support or chassis I3 to-'the rearward end of which are secured pillow blocks I4 in whichisjournaled an axle I5 carrying ground wheels I6 spaced apart from one another a sufficient distance to permit freedom of action of the rotary cutter v'I I. Vertical swivel bearings I'I are secured to the forward end of the chassis I3 and these'carry vertical pivot shafts I8 onV the lower end orf-which are mounted yokes or forks I9 carrying axles 2|) which rotatably support wheels 2|. Boltedvor otherwise secured to thechassis I3 is' a motor, generally designated 22, lsuch as an vinternal oombustion engine having a `vertical output shaft 23, It will be understood, however, that the invention is not limited to a vertical shaft but may equally well be employed on a horizontalsha'ft or on a vertical shaft Whichis connected to a reduction gear box, gearing or the like, or totl motor with a horizontal output shaft. f The motor shaft 23 is provided with Va powertransmitting portion such asa key seat 24 adapted to receive a` key 25 of a conventional type, for example, a Woodruff key, and this keydrivingly engages a keyway- 26 formed inthe major lpart 2l of a hub unit,V generally designated 28 land shown complete in Figures 2'an'd 3.- The major hub portion 2 is in the form of a collar 29 having' an annular'flange 30 extending transverselir therefrom and has a bore 3I through both the vcollar 29 and flange 311.` The bore 3I at ione side is provided with the keyway 26 inthe formof a longitudinal groove extending from one end to the other of the bore 3|. A slightly enlarged counterbore 32 extends inward fro-m the free end 33 of the collar portion 29 and is flared as at 34 to facilitate the insertion of a closure member in the form of an annular plug 35 as well as to provide space for welding metal, as described below. The plug 35 is in the form of a ring having an outer surface 36 of approximately the same diameter as the counterbore 32 with sufcient clearance to permit its insertion, the annular shoulder 3l between the bore 3| and counterbore 32 serving as a stop for the upper end 38 of the plug 35. A bore 39 is formed through the center of the plug 35 for the insertion of a fastener, such as the cap screw 40 shown in Figures 2 and 3. The plug 35 is of approximately the same thickness as the depth of the counterbore 32. The collar portion 29 of the hub part 21 is provided with an externally threaded portion 4I and is also slotted longitudinally as at 42. The hub unit 28 is assembled by inserting the plug 35 in the counterbore 32 so that its lower end 43 is substantially flush with the lower end 33 of the hub part 21, and is then welded in position as at 44 (Figure 2). The hub unit 28 is then ready for application to the lower end of the motor shaft 23 which is provided with a threaded bore 45 adapted to receive the threaded portion of the cap. screwx orother fastener 40.

The hub unit 23 forms the central portion of the slipping drive connection I which additionally includes a pair of friction washers 46 and mounted on opposite sides of a cutter bai; 4 8, and, having a washer 49 mounted beneath them ('Fi'gure 2), the washer 49 having; atoothl51hadapted to enter the slot 42. 1n this mannerathe washer- 49 is caused to rotate as a unit with the hub unit:

28. The washers 46l 41 and 4.9.and the cutter bar 48 are bored to approximately the same diameter as the collar portion 29 so as to slidef thereon and be held in position by a spring washer i and.- lock: nut.. 52.. the. latter being threaded upon the. threadedV portion 4:1- of. thehubfunit 23.. The cutter bar 4.8 has, cutter blades 53 secured as at 5A; toits opposite. ends. (Figure 1) A, skirt 55. is mounted om and. secured as. by welding; to an annular shoulder:` 5a on the. flangeportion 51 of the hubI part. 2L this being provided with an annular recessedsurface Safor thatpurpose. I-t Wilt beobrious thatmultiple grooves or slots 26, auch. asan internal spline, may be formed in the bore 3L. rather than the-singlekeyway 26.. shown in Figures 4 and 5..

ln. the operation of. thev inuention, letL it be assumed that the parts have been assembled in the, foregoing. manner, as shown 1n Figures- 1 to 3: inclusive. thesfastener Ml. is tightened and drawn upward.; to. its innermost position in the th-raeadedbore 45, the; plug portion.. 35,. of the hub unit. 2-8 drawn. tightly against the lower end 59 of ther shaft 23.. In this. manner,A the upper surfacaliV of the hubunit-28. is prevented from. engaging the lower end tl of the casing 62 ofthe motor 22 (Figure 2)Y and a suihcient. clearance is set,Y up.- therebetweerr to prevent. rubbing. The: motor is started,V causing the rotary member LL to. rotateLmoving. the cutter blades 53 through a circular path.. The operator pushes the machine l2 forward by means o the usual handle 612,. so that the, cutter blades 53 cut thegrass., A guard or skirt e5. attachedlto.. the chassis 1.3 and Surrounding, the cutter |I prevents injury to. the operator and4 also. prevents thev cut grass or leaves from. :dying outward..

If, however, an obstruction is encountered which oers greater resistance than the motor I2 can safely handle, the cutter bar 48 halts by reason of the slipping frictional connection between it and the friction washers 4B and 41. The motor shaft 23, however, can continue rotating safely without breakage until the motor 22 is eitherstoppedc orthe lawnmower` lf2 retracted so as toiremcve theobstruction.. The cupped washer 5| is of resilient material and applies a constant pressure to the washer 49 from the threaded lock nut 52, thereby creating the frictional slipping connection described above.

Whatl claixm is;

A: hubf unitv for holding a motor-driven rotary elementcomprisingx a hollow cylindrical tubular member having an abutment flange adjacent one end thereof and an externally-screW-threaded pQxiixm on the opposite end thereof, said tubular member having an outer cylindrical rotary-element,receiving surface and an inner cylindrical motor-shaft-receiving bore coaxial. therewith and havingl a` longitudinally-disposed. drive-transmitting7 groove therein, said tubular member also having a counterbore of larger diameter, than saidbore coaxial. with and opening into. said bore from the threaded endy thereof, said. cylindrical outer surface of. said tubular member having a rotary element. drive-transmitting portion there.- onf, and an annular closureA member snugly secured in said counterbore and unitedxedly and permanently to'said tubular member against relative motion therebetween, said closure member having a central fastener-receiving hole therethrough coaxial with said bore-and counterbore.

HAROLD L. BLYDENBURGH.

Reterences. Cited in. the le of this. patent UNITED STATES. PATENTS.'

Number Name Date 396,642.` Ball Jan. 22, 1889 634,256 Atherton Oct. 3, i899 1,904,203. Ross Sept. 26,v 1911 1,039,125 Hardy Sept. 24, 1912 1,288,136' Neuteboom Dec. 1-7, 19-18 1,4r3fisf133. Ettinger Nov; 7, 1922 lr83Ll25 Clbel'g Dec. l, 1931 2,3'QOAB8 Garnab Oct. 17, 1944 2,407,239 Albrecht. Sept; 10, 1946 2,419,859 Morris Apr. 29, 1947 2,152,558 Hahn oct.. 26, 1948 

